Information terminal

ABSTRACT

An information terminal for imaging a first object at a normal distance and a second object nearer than the first object readily with high precision. The information terminal has an imaging lens and an imaging device for capturing an image formed by the imaging lens. The imaging lens is a multifocal lens and composed of a first lens portion having a first focal length for imaging the first object (e.g., the user of the information terminal) at a normal distance and a second lens portion having a second focal length for imaging the second object (e.g., a bar code) nearer than the first object. The first and second lens portions are arranged on the same plane and formed in one piece. The information collected by imaging the second object is used for processing such as communication and display

TECHNICAL FIELD

[0001] The present invention relates to information terminals having an image input function such as a personal digital assistant (PDA), a mobile telephone (including the Personal Handy-phone System (PHS)), a remote controller for consumer electronics such as a television or a videocassette recorder, a personal computer equipped with a camera, a monitoring camera, and so forth. For example, the information terminal can be used for imaging a still image or a moving image of an object at a normal distance such as the user of the information terminal or for reading a close up still image such as a digital code, characters, or the like with high precision. Then, the read image is displayed as it is, or the read image data is decoded to collect the information included in the digital code or the characters therein, so that the collected information can be displayed or used for various processing such as communication or the like.

BACKGROUND ART

[0002] Generally, regarding an information terminal having an image input function such as a charge coupled device (CCD) or the like, it is quite advantageous to be capable of reading an approximate image of a bar code that is one kind of digital codes, while it is capable of reading a desired image such as, for example, an image of the user himself/herself or the scenery. Because the bar code can represent various information such as, for example, a mail address, a homepage address, a telephone number, a facsimile (FAX) number, a company name, a belonging section, a job title, or the like, use of such information in combination with the above-mentioned desired image can contribute to realize a highly effective communication.

[0003] Conventionally, a specialized scanner has been used for reading a bar code. There are examples of reading bar codes by using image input devices such as personal computers or the like. In such cases, an image input lens for imaging an object at a normal distance such as the user or the scenery ranging from a short distance (e.g., approximately 0.3 m) to a long distance has been used for reading a bar code.

[0004] However, using the above mentioned specialized scanner is highly complicated in operation and handling, and thus it is inconvenient in practical use. In addition, when the lens for imaging an object at a normal distance is used to read a bar code as described above, it is difficult to read a complicated image due to an insufficient resolution, especially a two-dimensional bar code or the like, to decode and recognize the information included in the image.

[0005] As a solution for this problem, it is conceivable to prepare one normal lens for imaging an object at a normal distance (e.g., the user) and one close-up lens for imaging an object nearer than the object at a normal distance (e.g., a bar code), and appropriately selecting or switching the imaging lens to use by revolving a platter on which the imaging lenses are attached or by sliding these imaging lenses. However, such operation is complicated and inconvenient in practical use, and moreover, such constructions hinder a miniaturization of the information terminal.

[0006] Accordingly, it is desirable that an information terminal has an image input function to image not only an object at a normal distance such as the user, scenery, or the like, but also an object such as a bar code nearer than the object at a normal distance readily with high precision.

[0007] Therefore, an object of the present invention is to provide an information terminal which is capable of imaging a first object at a normal distance and a second object nearer than the first object readily with high precision.

DISCLOSURE OF THE INVENTION

[0008] The present invention provides an information terminal having an imaging lens and an imaging device for capturing an image formed by the imaging lens, which is characterized in that the imaging lens is a multifocal lens composed of a first lens portion having a first focal length for imaging a first object at a normal distance and a second lens portion having a second focal length for imaging a second object nearer than the first object, and the first and second lens portions are arranged on the same plane and formed in one piece.

[0009] Here, the “normal distance” means a distance from a minimum depth of focus (e.g., 0.3 m) of the first lens portion to infinity. The “second object nearer than the first object” means that the second object is relatively nearer to the imaging lens than the first object.

[0010] To be “formed in one piece” means that the first lens portion and the second lens portion may be formed as separated members and thereafter formed in one piece, or the first lens portion and the second lens portion may be processed and formed using one member. In a case that the lenses are formed as separate members, they can either be the same materials or the different materials.

[0011] The “first object” means specifically, for example, a face or body of the user, scenery at a far distance, or the like, and the “second object” means specifically a digital code such as a bar code, characters or the like.

[0012] As the “imaging device,” specifically, a complementary metal-oxide semiconductor (CMOS), a charge coupled device (CCD), or the like can be adopted.

[0013] When an image memory for storing images captured by the imaging device is provided, specifically, a random access memory (RAM), an electrically erasable and programmable ROM (EEPROM), or the like can be adopted as the image memory.

[0014] According to the present invention, a first object at a normal distance from a minimum depth of focus (e.g., 0.3 m) to infinity is imaged by the first lens portion and captured in the imaging device, and a second object placed nearer than the first object is imaged by the second lens portion and captured in the imaging device.

[0015] Consequently, a much higher resolution than the conventional art can be achieved because the second object is imaged by imaging a second object by the second lens portion having a second focal length which is different from a first focal length of the first lens portion.

[0016] The first and second lens portions are arranged on the same plane and formed in one piece to compose one imaging lens. Different from a case that two imaging lenses are used for respectively imaging a first and second objects, it is not necessary to perform a complicated operation such as selecting or switching the imaging lens to use by revolving a platter on which the imaging lenses are attached or by sliding both the imaging lenses, so that an imaging can be performed readily and quickly. Furthermore, the information terminal can be reduced in weight and be miniaturized, to thereby make it advantageous for portability.

[0017] A switching of the first lens portion and the second lens portion can be performed readily and quickly by dividing a screen of the imaging device, thereby making it highly advantageous for practical use. Further, the switching of the lens portions is practically possible even when a same screen of the imaging device by switching the object to image between a first object and a second object, thus accomplishing the above-mentioned purposes.

[0018] In the above-mentioned information terminal of the present invention, the same plane is most desired to be orthogonal to an optical axis of the imaging lens.

[0019] Furthermore, in the above described information terminal of the present invention, it is desirable that a front shape of the first lens portion is any on of a circular shape, an oval shape, and a polygonal shape, and a front shape of the second lens portion is a ring shape. Then the second lens portion is desirable to be arranged outside the first lens portion in concentric with the first lens portion.

[0020] Here, the “front shape” means a shape of the imaging lens viewed from a direction along an optical axis of the imaging lens. For the lens portion arranged inside, the front shape means a shape of an outer periphery outline (outer edge shape) viewed from a direction along an optical axis of the imaging lens. For the lens portion arranged outside, the “front shape” means a shape of an outer periphery outline (outer edge shape) and a shape of an inner periphery outline (inner edge shape) viewed from a direction along an optical axis of the imaging lens.

[0021] The “polygonal shape” is preferred to be line symmetry or point symmetry. Further, it is not necessary to be a regular polygon. The corners of the “polygonal shape” can be rounded or chamfered.

[0022] To be “arranged outside the first lens portion” means that the second lens portion may be arranged in direct contact with the outer edge of the first lens portion, or the second lens portion may be arranged outside the outer edge of the first lens portion, for example, with a ring shape member intervened therebetween. However, the arrangement in direct contact with the outer edge of the first lens portion is preferable in terms of simplification and stabilization of structure and facilitation of manufacture.

[0023] To be “arranged in concentric” means that the first lens portion and the second lens portion are arranged in such a manner that the optical axis of the first lens portion coincides with the optical axis of the second lens portion.

[0024] The first and second lens portions being formed to have those above-mentioned front shapes contribute to a simplification of structure, a facilitation of manufacture, a simplification of obtaining a high quality image, and an improvement of decoding precision. Especially, a highly desirable result can be obtained by a concentric composition in which the front shape of the first lens portion is a circular shape, and the front shape of the second lens portion is a ring shape.

[0025] The above-mentioned arrangement of the first and second lens portions may be reversed, and still the identical effect can be obtained in this case. In other words, in the above-mentioned information terminal of the present invention, the front shape of the first lens portion may be a ring shape, and the front shape of the second lens portion may be any one of a circular shape, an oval shape, and a polygonal shape. Then, the first lens portion may be arranged outside the second lens portion in concentric with the second lens portion. Especially, a highly desirable result can be obtained by a concentric composition in which the front shape of the first lens portion is a ring shape, and the front shape of the second lens portion is a circular shape.

[0026] In either case the first or second lens portion is the lens portion arranged outside, its front shape may have an outer edge shape and an inner edge shape different to each other. For example, the outer edge shape may be a polygonal shape while the inner edge shape is a circular shape. In other words, the outer edge shape of the lens portion arranged outside may be different from the outer edge shape of the lens portion arranged inside.

[0027] Further, the inner edge shape of the lens portion arranged outside may be different from the outer edge shape of the lens portion arranged inside. In other words, there may be formed a gap between the inner edge of the lens portion arranged outside and the outer edge of the lens portion arranged inside.

[0028] Furthermore, in the above described information terminal of the present invention, the front shape of the first lens portion may be any one of one portion of a circular shape, one portion of an oval shape, and one portion of a polygonal shape, and the front shape of the second lens portion may be any one of the other portion of a circular shape, the other portion of an oval shape, and the other portion of a polygonal shape. Then, the first and second lens portions may be arranged in such a manner that a linear portion formed on the outline of the first lens portion is arranged in direct contact with a linear portion formed on the outline of the second lens portion.

[0029] Here, the meanings of the “front shape” and the “polygonal shape” have already been explained above.

[0030] The “one portion of a circular shape” and the “other portion of a circular shape” are one and the other portions divided from one circular shape being cut in straight line. The straight line to cut the circular shape is not necessarily being a diameter line on the center of the circular shape.

[0031] The “one portion of an oval shape” and the “other portion of an oval shape” are one and the other portions divided from one oval shape being cut in straight line. The straight line to cut the oval shape is not necessarily being a long axis line or a short axis line on the center of the oval shape.

[0032] The “one portion of a polygonal shape” and the “other portion of a polygonal shape” are one and the other portions divided from one polygonal shape being cut in straight line. The straight line to cut the polygonal shape is not necessarily being a center line of symmetry when the polygonal shape is line symmetry, or the straight line is not necessary being on a center point of symmetry when the polygonal shape is point symmetry.

[0033] When adopting this composition, the first lens portion may either be arranged or not arranged in concentric with the second lens portion. In other words, an optical axis of the first lens portion may either coincide or not coincide with an optical axis of the second lens portion.

[0034] One example of a manufacturing method of the multifocal imaging lens described above will be explained with references to FIG. 16 to FIG. 18. In addition, FIG. 16 to FIG. 18 are explanatory views, and the first and second lens portions of the present invention are not restricted to the shapes shown in these views.

[0035] As shown in FIG. 16, a long focal length lens 465 and a short focal length lens 466 are prepared. A center portion 465 a of the long focal length lens 465 and a peripheral portion 466 b of the short focal length lens 466 are combined as shown in FIG. 17. Accordingly, there is obtained an imaging lens 422 with the center portion 465 a having a circular front shape of the long focal length lens 465 as a first lens portion 461 and the peripheral portion 466 b having a ringed front shape of the short focal length lens 466 as a second lens portion 462.

[0036] In addition, the relation of the lenses 465 and 466 may be reversed to compose a mutifocal imaging lens with a periphery portion having a ringed front shape of the long focal length lens 465 as the first lens portion, and a center portion having a circular front shape of the short focal length lens 466 as the second lens portion.

[0037] Further, since an imaging lens used in the present invention is satisfactory as long as it is composing a first and second lens portions with different focal lengths to each other, the imaging lens may be formed, for example, not only by separately forming two glass lenses with different focal lengths to each other and thereafter composing them to one piece as described above but also by processing plastic such as an acrylic resin or the like to form the first and second lens portions in one piece at the same time.

[0038] In the former case, a border line of the first lens portion and the second lens portion will be a distinct line. In the latter case, a border line of the first lens portion and the second lens portion will be smooth without any distinct line, but it does not hinder the practical use.

[0039] On the other hand, the front shape of the first lens portion may be any one of one portion of a circular shape, one portion of an oval shape, and one portion of a polygonal shape, and the front shape of the second lens portion is any one of the other portion of a circular shape, the other portion of an oval shape, and the other portion of a polygonal shape, and then a linear portion formed on the outline of the first lens portion is arranged in direct contact with a linear portion formed on the outline of the second lens portion as described above. In this case, two glass lenses with different focal lengths to each other may be separately formed and thereafter composed to one piece, or plastic may be processed to form both the lens portions in one piece at the same time. When plastic is processed like the latter case, a border line of the first lens portion and the second lens portion will be smooth without any distinct line, but it does not hinder the practical use.

[0040] For the information terminal of the present invention, glass or plastic is the preferable material to form the imaging lens.

[0041] Furthermore, the information terminal of the present invention may be structured to have an image memory for storing images captured by the imaging device, in which a first image obtained by imaging a first object is formed in a first image-forming section in the imaging device and then stored in the image memory as a first image signal, and a second image obtained by imaging a second object is formed in a second image-forming section in a different region from the first image-forming section in the imaging device and then stored in the image memory as a second image signal.

[0042] In this manner, the first and second image-forming sections are formed in different regions in the imaging device, so that a switching of the first and second lens portions can be performed readily and quickly by dividing a screen of the imaging device, thereby making it highly advantageous for practical use.

[0043] Accordingly, it is desirable that the information terminal of the present invention is structured to have an image memory which stores a first image obtained by imaging a first object as a moving image or a still image and a second image obtained by imaging a second object as a moving image or a still image. In this structure, a first image such as a moving image of the user or the like and a second image such as a still image of a bar code or the like can be stored in the image memory.

[0044] In the above described information terminal of the present invention, a second object is a digital code or characters, and it is desired to have a decoding means for decoding a digital code or characters and a communication means for performing communication based on the information included in a digital code or characters which are decoded by the decoding means.

[0045] The “digital code” includes, for example, a one-dimensional or two-dimensional bar code or the like. The “communication means” may be, for example, a wireless transmitting/receiving mechanism provided in a mobile telephone (including the PHS) or the like, or it may also be, for example, a communication means through a wired network such as the internet, a LAN, or the like.

[0046] When the information terminal is structured to have the decoding means and the communication means, it is capable to have communication based on the information included in a decoded digital code or characters to perform various processing such as making a telephone call to the decoded phone number, downloading a homepage to display from the decoded homepage address, or the like.

[0047] In the information terminal structured to have the decoding means and the communication means as described above, it is also desirable to have a notification means for notifying a completion of decoding process of the decoding means. As the notification means, for example, a speaker for producing a voice or a confirmation sound upon a completion of decoding process of the decoding means, a light-emitting mechanism for emitting a light upon a completion of decoding process of the decoding means, or the like can be preferably used.

[0048] When the notification means is provided, the user of the information terminal can be easily notified of the completion of decoding process.

[0049] When the information terminal is structured to have the decoding means and the communication means as described above, it may further include a display means for displaying a completion of decoding process of the decoding means. When the display means is provided, the user of the information terminal can confirm the completion of decoding process on a screen of the display means.

[0050] Further, when the information terminal is structured to have the decoding means and the communication means as described above, it is desirable to have a display means for displaying at least one of either decoding result of the decoding means or communication result of the communication means. When the display means for displaying a decoding result or a communication result is provided, the user of the information terminal can obtain various information by referring to the display means, so that the function of information terminal can be improved.

[0051] Further, in the information terminal of the present invention as described above, an optical shutter to switch the first and second lens portions may be arranged between the imaging lens and the imaging device. As the “optical shutter,” for example, a shutter using the liquid crystal or the like is excellent in practical use. When the optical shutter is arranged in this manner, an image with high contrast between light and shade can be formed.

[0052] In the above described information terminal of the present invention, it is desirable to have a light-emitting means for producing a flashlight synchronously with scan timing of the imaging device when imaging a second object. As the “flashlight,” not only a flashlight produced by a regular photographic flashlight, but also a flashlight produced by an infrared flash, an ultraviolet flash, or the like can be used.

[0053] When the light-emitting means is provided, the information terminal can produce a flashlight synchronously with scan timing of the imaging device when imaging a second object that is normally in close proximity, so that a shade of the user or the like can be effectively prevented from occurring, and thus a clear image can be obtained, thereby making it advantageous for imaging a second object.

[0054] In the above described information terminal of the present invention, it is desirable to have a detection means for detecting a saturation current from the imaging device and a drive means for driving a drive circuit of the imaging device according to a signal from the detection means. When adopting this structure, the saturation electron from the imaging device can be used to detect an appropriate storage time. Accordingly, the storage time of the light can be lengthened to improve sensitivity.

[0055] Further, in the above described information terminal of the present invention, it is desirable to have a color filter, which is used when imaging a second object, arranged on at least one side of a front or back face of the imaging lens. Here, the “color filter” is a tight filter that is pervious to the light with specific wavelength and is impervious to the light with the other wavelengths.

[0056] When the color filter is provided, it is possible to let the light with specific wavelength emitted from a second object penetrates the imaging lens while lights with the other wavelengths is blocked, so that a second object can be imaged with high contrast. For example, when a second object is a bar code or the like printed in invisible ink, the light with a wavelength of the invisible ink, which is emitted upon irradiation of excitation light to the bar code, penetrates the color filter while the light with the other wavelength is blocked, so that the image from the invisible ink can be clearly imaged.

[0057] Furthermore, the above described information terminal of the present invention, it is desirable to have an image memory for storing an image of a second object captured by the imaging device, the image memory plurally divided for each color, and a compensation means for compensating a signal stored in one of divided image memories for respective colors according to a signal stored in one of the other image memories for respective colors.

[0058] Here, the “image memories divided for respective colors” are, for example, image memories respectively divided for the three colors of an image signal such as a red image memory, a green image memory, a blue image memory or the like.

[0059] When the compensation means is provided, a signal stored in one of the image memories for respective colors can be compensated according to a signal stored in one of the other image memories in relation to an image obtained by imaging a second object, that is, an advantage for improving the contrast of an image to obtain a clear image of the second object. Consequently, when the second object is a bar code or the like, it is possible to precisely read the information included in this bar code.

[0060] Furthermore, in the above described information terminal of the present invention, it is desirable to have a difference operation processing means for producing an image of a second object based on a difference between an image signal obtained by imaging with irradiation of excitation light on the second object and an image signal obtained by imaging without irradiation of excitation light. Here, as the “excitation light,” a light with a shorter wavelength (e.g. an ultraviolet ray) than the light emitted from the fluorescent material being used is adopted. When the fluorescent material emits an infrared region light, an infrared light that is close to the visible light can be used.

[0061] When the difference operation processing means is provided, an imaging of a second object that emits a fluorescent light is performed with irradiation of excitation light to excite the fluorescent light, and then an image of the second object is obtained from a difference between the image signal obtained by the irradiation of excitation light and the image signal obtained without the irradiation of excitation light. Accordingly, it is highly advantageous for detecting a bar code formed by such kind of ink that emits light under irradiation of excitation light.

[0062] Furthermore, in the above-mentioned information terminal, it is desirable to have a display means for displaying information on a screen and an illumination means attached to the display means for illuminating a second object by illumination from the screen of the display means when imaging the second object. Here, as the “display means,” for example, a liquid crystal display device or the like can be preferably used.

[0063] When the illumination means for illuminating a second object by illumination from the screen of the display means is provided, a reading of the second object is performed while it is illuminated by the illumination means in order to obtain a clear image of the second object, thereby improving the decoding precision.

[0064] Furthermore, in the above-mentioned information terminal, it is desirable to include an antenna for wireless transmitting and receiving. The antenna in a storage status is preferred to have a length that optimizes a distance between a second object arranged on a surface to which the top of the antenna comes in contact with and the second lens portion. The length of antenna defined in this manner enables an easy, quick, and precise optimization of the distance between the second lens portion and the second object when imaging the second object to thereby obtain a high quality image.

BRIEF DESCRIPTION OF DRAWINGS

[0065]FIG. 1 is an overall structure view showing an information terminal of a first embodiment of the present invention;

[0066]FIG. 2 is an explanatory view showing an effect of an imaging lens of the information terminal of the first embodiment;

[0067]FIG. 3 is an explanatory view showing an effect of an imaging lens provided in an information terminal of a second embodiment of the present invention;

[0068]FIG. 4 is an overall structure view showing an information terminal of a third embodiment of the present invention;

[0069]FIG. 5 is an enlarged view showing an imaging lens of the information terminal of the third embodiment;

[0070]FIG. 6 is an explanatory view showing an effect of the imaging lens of the information terminal of the third embodiment;

[0071]FIG. 7 is an explanatory view showing another effect of the imaging lens of the information terminal of the third embodiment;

[0072]FIG. 8 is an overall structure view showing an information terminal of a fourth embodiment of the present invention;

[0073]FIG. 9 is an overall structure view showing an information terminal of a fifth embodiment of the present invention;

[0074]FIG. 10 is an overall structure view showing an information terminal of a sixth embodiment of the present invention;

[0075]FIG. 11 is an overall structure view showing an information terminal of a seventh embodiment of the present invention;

[0076]FIG. 12 is an explanatory view showing a usage of an information terminal of an eighth embodiment of the present invention;

[0077]FIG. 13 is an explanatory view showing a usage of an information terminal of a ninth embodiment of the present invention;

[0078]FIG. 14 is an overall structure view showing an information terminal of a tenth embodiment of the present invention;

[0079]FIG. 15 is an explanatory view showing a usage of an information terminal of an eleventh embodiment of the present invention;

[0080]FIG. 16 is a view showing a manufacturing method of a multifocal imaging lens provided in an information terminal of the present invention;

[0081]FIG. 17 is another view showing the manufacturing method of the multifocal imaging lens provided in the information terminal of the present invention; and

[0082]FIG. 18 is still another view showing the manufacturing method of the multifocal imaging lens provided in the information terminal of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0083] To describe the present invention in detail, the present invention will be explained with reference to the drawings.

[0084] (First Embodiment)

[0085]FIG. 1 is an overall structure view showing an information terminal 1 of the first embodiment of the present invention. FIG. 2 is an explanatory view showing an effect of an imaging lens 22 of the information terminal 1.

[0086] In FIG. 1, the information terminal 1 includes the imaging lens 22 for imaging first and second objects 81 and 82 (refer to FIG. 2), an imaging device 21 for capturing an image formed by the imaging lens 22, a camera control unit (hereinafter, abbreviated to “CCU”) 11 for controlling image qualities of image signals of the first and second objects 81 and 82 abstracted from the imaging device 21, an image memory 12 for storing the image signals processed by the CCU 11 as moving images or still images.

[0087] The information terminal 1 also includes a drive circuit 14 for driving the imaging device 21, a central processing unit (hereinafter, abbreviated to “CPU”) 15 for performing an operation processing on image signals of the second object 82 stored in the image memory 12, a control program 16 that prescribes an operating procedure for the CPU 15, and a power supply 19 for supplying necessary power to each circuit.

[0088] As the imaging device 21, a complementary metal-oxide semiconductor (CMOS), a charge coupled device (CCD), or the like can be adopted.

[0089] The imaging lens 22 is composed of a first lens portion 61 made of glass for example, and a second lens portion 62 made of glass for example. The first and second lens portions 61 and 62 are arranged on the same plane and formed in one piece, and thus the imaging lens 22 is formed as a multifocal lens. The plane on which the first and second lens portions 61 and 62 are arranged is orthogonal to an optical axis of the imaging lens 22. In this first embodiment, a border line between the first lens portion 61 and the second lens portion 62 is a straight line for example, and a lower edge portion of the first lens portion 61 having a front shape in semicircular shape for example and an upper edge portion of the second lens portion 62 having a front shape in semicircular shape for example are arranged in contact with each other.

[0090] The CPU 15 and the control program 16 compose a decoding means for decoding an image data of the second object 82 such as a bar code for example, which is one kind of digital codes, in order to recognize the information included in the image data of the second object 82.

[0091] Further, the information terminal 1 includes a detecting means not shown in the view for detecting a saturation current from the imaging device 21, and a drive means not shown in the view for driving the drive circuit 14 of the imaging device 21 according to a signal from the detecting means.

[0092] In the first embodiment, the information terminal 1 performs an imaging of the first and second objects 81 and 82 as follows.

[0093] In FIG. 2, the focal length of the first lens portion 61 is, for example, 5 mm. By this first lens portion 61, the first object 81 at a normal distance such as an object in the vicinity (e.g., a face of a user of a mobile telephone at a distance of 0.3 m), the scenery at a far distance, or the like is formed in image in a first region of the imaging device 21 as a first image 91. The region in which the image 91 is formed corresponds to a first image-forming section of the present invention. On the other hand, a focal length of the second lens portion 62 is, for example, 4.3 mm. By this second lens portion 62, the second object 82 such as a bar code for example, which is one kind of digital codes or the like, nearer than the first object 81 is formed in image in a second region of the imaging device 21 as a second image 92. The region in which the image 92 is formed corresponds to a second image-forming section of the present invention.

[0094] First, the first object 81 is imaged using the first lens portion 61, and then the imaging device 21 is driven by the drive circuit 14, so that an image signal of the first image 91 is abstracted from the imaging device 21. Thereafter, the obtained image signal of the first object 81 is processed in CCU 11 and then stored in the image memory 12 as a moving image or a still image. In this first embodiment, the distance between a principal plane of the first lens portion 61 and the imaging device 21 is defined to be 5 mm to 5.1 mm for example.

[0095] Further, as shown in FIG. 2, shields 63 are placed in the vicinities of the first and second lens portions 61 and 62 of the imaging lens 22 in order to prevent the light passing through the second lens portion 62 from reaching the image-forming section of the first image 91 in the imaging device 21.

[0096] Next, a two-dimensional bar code at a distance of approximately 30 mm for example is imaged as the second object 82. At this time, the second object 82 is imaged using the second lens portion 62, and then the imaging device 21 is driven by the drive circuit 14 to abstract an image signal of the second image 92. Thereafter, the obtained image signal is stored in the image memory 12 as a still image. Since the light shields 63 are placed in the vicinities of the first and second lens portions 61 and 62 as described above, the light passing through the first lens portion 61 is similarly prevented from reaching the image-forming section of the second image 92. Subsequently, the image signal of the second object 82 stored in the image memory 12 as a still image is subjected to the operation processing by the CPU 15 using the control program 16. In addition, the necessary power for each of the above circuits is provided by the power supply 19.

[0097] According to the first embodiment, the following effects are presented. Since the imaging lens 22 is composed of the first and second lens portions 61 and 62 with different focal lengths to each other, the first object 81 at a normal distance from a minimum depth of focus (e.g., 0.3 m) to infinity can be imaged by the first lens portion 61 and stored in the image memory 12 as a moving image or a still image, and a second object 82 (e.g., a bar code) placed nearer than the first object 81 can be imaged by the second lens portion 62 and stored in the image memory 12 as a still image. Consequently, a much higher resolution than the conventional art can be obtained.

[0098] In addition, the first and second lens portions 61 and 62 are arranged on the same plane, and these lens portions 61 and 62 are formed in one piece to compose the imaging lens 22, so that it is not necessary to perform a complicated operation such as revolving or sliding to switch or replace lenses. Accordingly, an imaging can be performed simply.

[0099] Furthermore, because the detection means and the drive means not shown in the view are provided, it is capable of detecting an appropriate storage time by utilizing a saturation current which the imaging device 21 outputs. Accordingly, the storage time can be lengthened to improve sensitivity.

[0100] In addition, an optical shutter to switch the first lens portion 61 and the second lens portion 62 may be arranged between the imaging lens 22 and the imaging device 21. Consequently, an image can be formed in much higher contrast between light and shade.

[0101] (Second Embodiment)

[0102]FIG. 3 is an explanatory view showing an effect of an imaging lens provided in an information terminal 102 of a second embodiment of the present invention.

[0103] In FIG. 3, the information terminal 102 has a structure excluding the shields 63 (refer to FIG. 2) which are respectively placed in the vicinities of the first and second lens portions 61 and 62 in the information terminal 1 of the aforementioned first embodiment. Since the rest of the structure is the same as that of the information terminal 1 of the aforementioned first embodiment, the same reference numerals are designated to the same components to omit explanations in detail, and only the different components will be explained below.

[0104] As shown in FIG. 3, when the shields 63 are removed, a light 91 a (dashed line in the view) that passes through the first lens portion 61 is incident on the whole plane of the imaging device 21. Similarly, a light 92 a (solid line in the view) that passes through the second lens portion 62 is incident on the whole plane of the imaging device 21. Consequently, when imaging the first object 81, a light passed through the second lens portion 62 incidents on the imaging device 21 as a light not formed in image, which lowers the contrast. However, the contrast is compensated by the CCU 11 to obtain a substantially normal image. Similarly, when imaging the second object 82, a light passed through the first lens portion 61 incidents on the imaging device 21 as a light not formed in image, which lowers the contrast. However, the contrast is compensated by the CCU 11 to obtain a substantially normal image.

[0105] Therefore, the information terminal 102 in this second embodiment excluding the shields 63 can present the identical effects to those of the information terminal 1 of the first embodiment.

[0106] (Third Embodiment)

[0107]FIG. 4 is an overall structure view showing an information terminal 3 of a third embodiment of the present invention, and FIG. 5 is an enlarged view showing an imaging lens 322 of the information terminal 3. The FIG. 6 and FIG. 7 are explanatory views showing effects of the imaging lens 322 of the information terminal 3.

[0108] In FIG. 4, the information terminal 3 has the structure of the information terminal 1 (refer to FIG. 1) of the aforementioned first embodiment, to which are added a liquid crystal display device 13 as a display means for displaying various information on a screen, a not-shown optical shutter arranged between the imaging lens 322 and an imaging device 21, a switching circuit 17 for switching and selecting a first lens portion 361 and a second lens portion 362 by the optical shutter, a switch 20 for operating the switching circuit 17, and a decoded information memory 18 for storing information obtained by decoding an image data of the second object 82 (refer to FIG. 7). Furthermore, the information terminal 3 includes the imaging lens 322 having a different composition from the imaging lens 22 of the aforementioned first embodiment. Since the rest of the structure is the same as that of the information terminal 1 of the aforementioned first embodiment, the same reference numerals are designated to the same components to omit explanations in detail, and only the different components will be explained below.

[0109] In FIG. 5, the imaging lens 322 is composed of a first lens portion 361 made of glass for example, and a second lens portion 362 made of glass for example. The first lens portion 361 has a front shape in circular shape for example and is arranged at the center. On the other hand, the second lens portion 362 has a front shape in ring shape (doughnut shape) for example and is arranged outside the first lens portion 361 in contact with the outer edge portion of the first lens portion 361. These first and second lens portions 361 and 362 are arranged and formed in one piece in such a manner that their optical axes coincide with each other, and in other words both the lens portions are arranged in concentric with each other. In this manner, the imaging lens 322 is formed as a concentric multifocal lens. In addition, the plane on which these first and second lens portions 361 and 362 are arranged is orthogonal to the optical axis of the imaging lens 322.

[0110] As the optical shutter, a liquid crystal shutter or the like is preferable in practical use. On this liquid crystal shutter, front and rear transparent electrodes are respectively arranged on opposing faces of front and rear transparent plates, and a liquid crystal substance layer is arranged and sealed therebetween. The liquid crystal shutter blocks a light when a voltage is applied to the above-mentioned liquid crystal substance layer, but the liquid crystal shutter let through a light when a voltage is not applied to the liquid crystal substance layer. Accordingly, each light that passes through the first lens portion 361 or the second lens portion 362 can be individually passed or blocked.

[0111] In the third embodiment, the information terminal 3 performs an imaging of the first and second objects 81 and 82 as follows.

[0112] When imaging the first object 81, the optical shutter of the second lens portion 362 is shut, and the imaging is performed only by the first lens portion 361 as shown in FIG. 6. When imaging the second object 82 (e.g., two-dimensional bar code), the optical shutter of the first lens portion 361 is shut, and the imaging is performed only by the second lens portion 362 as shown in FIG. 7. In this case, although the second lens portion 362 is ring shape, the light 64 from the object is concentrated at one point on focusing surface of the imaging device 21, so that an image in high contrast can be obtained.

[0113] When respectively imaging the first and second objects 81 and 82 using the first and second lens portions 361 and 362 of the imaging lens 322 as described above, the switching of the first and second lens portions 361 and 362 is performed by pressing the switch 20 that operates the switching circuit 17.

[0114] Thereafter, similarly to the aforementioned first embodiment, an image data of the first object 81 which is imaged using the first lens portion 361 is stored in the image memory 12 as a moving image or a still image. An image data of the second object 82 imaged using the second lens portion 362 is stored in the image memory 12 as a still image, and thereafter, this image data is subjected to the operation processing by the CPU 15 using the control program 16 to thereby display the image stored in the image memory 12 (e.g., an image or characters as it is of a two-dimensional bar code) as a still image as it is on the liquid crystal display device 13.

[0115] Furthermore, information included in an image data (e.g., information related to a two-dimensional bar code that is, namely, information having any particular meanings included in a two-dimensional bar code) of the second object 82, which is decoded by the decoding means composed of the control program 16 and the CPU 15, is stored in the decoded information memory 18, and this stored information is either displayed on the liquid crystal display device 13 or used for operating the CPU 15 to perform a sending and receiving (transmitting and receiving) of information. At this time, the sending and receiving of information is conducted with other devices or recording mediums which are connected to the information terminal 3 through a network such as the internet or a local area network (LAN), or simply through an indoor cable or the like. In addition, other information obtained by this sending and receiving of information may further be displayed on the liquid crystal display device 13.

[0116] According to the third embodiment, the following effects are presented. Similarly to the imaging lens 22 of the aforementioned first embodiment, since the imaging lens 322 is composed of the first and second lens portions 361 and 362 with different focal lengths to each other, the first object 81 can be imaged using the first lens portion 361, and a second object 82 can be imaged using the second lens portion 362. Consequently, a much higher resolution than the conventional art can be obtained.

[0117] In addition, similarly to the aforementioned first embodiment, the first and second lens portions 361 and 362 are arranged on the same plane, and these lens portions 361 and 362 are formed in one piece to compose the imaging lens 322, so that it is not necessary to perform a complicated operation such as revolving or sliding to switch or replace lenses. Accordingly, an imaging can be performed simply.

[0118] Furthermore, since the liquid crystal display device 13 is included, various information obtained from an image data of the second object 82 can be displayed. For example, when a two-dimensional bar code is imaged as the second object 82, the image of the two-dimensional bar code as it is can be displayed as a still image on the liquid crystal display device 13. Further, just by imaging a two-dimensional bar code, a telephone number, an internet homepage address or the like denoted by the two-dimensional bar code can be recognized, and these recognized information can be displayed on the liquid crystal display device 13. Furthermore, by conducting a sending and receiving of information with other devices, recoding mediums, or the like, a facial image of a calling party of the recognized telephone number, or a homepage screen corresponding to the recognized internet homepage address can be displayed on the liquid crystal display device 13.

[0119] In this third embodiment, the optical shutter is included, but it is possible to omit the placement of this optical shutter. Even when a placement of the optical shutter is omitted, an iris of the lens will still be stopped down when imaging the first object 81 since the first object 81 is normally bright, so that a main imaging is performed by the first lens portion 361 arranged at the center to thereby obtain a correctly focused first image. On the other hand, when imaging the second object 82, an image signal with sufficiently high contrast can be obtained by the second lens portion 362 in ring shape arranged at the peripheral portion, but an image of which the first lens portion 361 partakes is largely defocused, which lowers the contrast of the image from the second lens portion 362. However, since the second object 82 is a binary signal with a clear contrast between light and shade such as a bar code for example, the lowered contrast can readily be improved by signal processing, and thus it poses no problem in practical use. Furthermore, when the optical shutter is arranged between the imaging lens 322 and the imaging device 21 as described in this third embodiment, an image with much higher contrast between light and shade can be formed.

[0120] In addition, in this third embodiment, the first lens portion 361 is formed in a circular shape and arranged at the center, and the second lens portion is formed in a ring shape and arranged outside the first lens portion. However, the arrangement of both the lens portions may be reversed so that the second lens portion formed in a circular shape and arranged inside, and the first lens portion formed in a ring shape and arranged outside the second lens portion.

[0121] (Fourth Embodiment)

[0122]FIG. 8 is an overall structure view showing an information terminal 302 of a fourth embodiment of the present invention.

[0123] In FIG. 8, the information terminal 302 is a mobile telephone (including the PHS) or the like for example. The information terminal 302 has the structure of the information terminal 3 (refer to FIG. 4) of the aforementioned third embodiment, to which a wireless transmitting/receiving mechanism 31 as a communication means is added. Since the rest of the structure is the same as that of the information terminal 3 of the aforementioned third embodiment, the same reference numerals are designated to the same components to omit explanations in detail, and only the different components will be explained below.

[0124] In the fourth embodiment, similarly to the aforementioned third embodiment, information included in an image data (e.g., information included in a two-dimensional bar code) of the second object 82, which is decoded by the decoding means composed of the control program 16 and the CPU 15, is stored in the decoded information memory 18, and this stored information is used for operating the wireless transmitting/receiving mechanism 31 to perform a sending and receiving of information.

[0125] Therefore, in this fourth embodiment, the similar effects to those of the third embodiment can be obtained. In addition to the capability of imaging the first and second objects 81 and 82 readily with high precision, when the second object 82 is a two-dimensional bar code for example, the placement of the wireless transmitting/receiving mechanism 31 and the liquid crystal display device 13 enables to perform various processing based on the information included in the bar code such as, for example, making a telephone call to a telephone number denoted by the two-dimensional bar code by just imaging the two-dimensional bar code, downloading a homepage corresponding to an interment homepage address denoted by the two-dimensional bar code to thereby display the contents of this homepage on the liquid crystal display device 13, and so forth.

[0126] (Fifth Embodiment)

[0127]FIG. 9 is an overall structure view showing an information terminal 303 of a fifth embodiment of the present invention.

[0128] In FIG. 9, the information terminal 303 has the structure of the information terminal 302 (refer to FIG. 8) of the aforementioned fourth embodiment, to which a speaker 41 and a light-emitting mechanism 42 are added. Since the rest of the structure is the same as that of the information terminal 302 of the aforementioned fourth embodiment, the same reference numerals are designated to the same components to omit explanations in detail, and only the different components will be explained below.

[0129] The speaker 41 as a notification means is for generating a voice or a confirmation sound after an image data of the second object 82 (e.g., a two-dimensional bar code) is decoded, as a function to notify a completion of a decoding process to the user of the information terminal 303.

[0130] The light-emitting mechanism 42 as a notification means is for emitting a light signal after an image data of the second object 82 (e.g., a two-dimensional bar code) is decoded, as a function to notify a completion of a decoding process to the user of the information terminal 303.

[0131] In the fifth embodiment, similarly to the aforementioned fourth embodiment, information included in an image data (e.g., a two-dimensional bar code) of the second object 82 is decoded by the decoding means composed of the control program 16 and CPU 15, and thereafter the completion of the decoding process is notified to the user by at least one of either speaker 41 or light emitting mechanism 42. Further, the completion of the decoding process and a decoding result are displayed on the liquid crystal display device 13.

[0132] Therefore, in this fifth embodiment, the following effects can be obtained in addition to the similar effects to those of the aforementioned fourth embodiment. The placement of the speaker 41 and the light-emitting mechanism 42 enables to notify a completion of decoding process to the user, so that the user of the information terminal 303 can confirm a completion of decoding process. Furthermore, a decoding result can be displayed on the liquid crystal display device 13, so that the user can confirm the validity of a sending and receiving of information. Accordingly, misoperation by the user can be effectively prevented.

[0133] In addition, both the speaker 41 and light emitting mechanism 42 are included in this fifth embodiment, but either one of them may be omitted.

[0134] (Sixth Embodiment)

[0135]FIG. 10 is an overall structure view showing an information terminal 304 of a sixth embodiment of the present invention.

[0136] In FIG. 10, the information terminal 304 has the structure of the information terminal 302 (refer to FIG. 8) of the aforementioned fourth embodiment, to which an illumination control mechanism 43 and an illumination lamp 44 are added. Since the rest of the structure is the same as that of the information terminal 302 of the aforementioned fourth embodiment, the same reference numerals are designated to the same components to omit explanations in detail, and only the different components will be explained below.

[0137] The illumination lamp 44 is for illuminating the second object 82 and is turned on when imaging the second object 82, a bar code for example, arranged at a very close distance (e.g., approximately 30 mm).

[0138] The illumination control mechanism 43 is for supplying power to the illumination lamp 44 to turn it on.

[0139] According to this sixth embodiment, the following effects can be obtained in addition to the similar effects to those of the aforementioned fourth embodiment. When the information terminal 304 is a portable type, and if this portable type information terminal 304 itself blocks the illumination such as a ceiling area lighting, a natural light in a room, or the like, a clear image can still be obtained by the lighting of the illumination lamp 44, so that a decoding of information included in the second object 82 (e.g., a two-dimensional bar code) by the control program 16 and the CPU 15 can be easily performed. Especially, when the image signal from the CCU 11 is low level due to inadequate illumination, a signal corresponding to this image signal level is sent to the illumination control mechanism 43 in order to increase power supply to the illumination lamp 44, so that the level of the above-mentioned image signal can be increased.

[0140] In addition, instead of the illumination lamp 44 and the illumination mechanism 43 of this sixth embodiment, a light-emitting means for producing a flashlight synchronously with the scan timing of the imaging device 21 when imaging the second object 82 can be included to obtain the similar effects.

[0141] (Seventh Embodiment)

[0142]FIG. 11 is an overall structure view showing an information terminal 305 of a seventh embodiment of the present invention.

[0143] In FIG. 11, the information terminal 305 is a mobile telephone (including the PHS), which has an internal structure identical to that of the information terminal 302 (refer to FIG. 8) of the aforementioned fourth embodiment, so that the same reference numerals are designated to the same components to omit explanations in detail, and only the different components will be explained below.

[0144] The information terminal 305 includes an antenna 32, a speaker 33, dial buttons 34, and a microphone 35.

[0145] Similarly to the information terminal 302 of the aforementioned fourth embodiment, the information terminal 305 includes the second lens portion 362 that functions as a close-up attachment lens for imaging a second object 5.

[0146] When the antenna 32 is retracted to be in a storage status (the status shown in FIG. 11), a length of the antenna 32 can optimize a distance between a second object 5 arranged on a surface to which the top of the antenna 32 comes in contact with and the second lens portion 362.

[0147] In the seventh embodiment, the information terminal 305 performs an imaging of the second object 5 as follows.

[0148] For example, when imaging the second object 5 that is for close-up imaging (e.g., a two-dimensional bar code) placed on top of a desk 51, the image of the second object 5 is formed in the imaging device 21 using the second lens portion 362. At this time, a distance between the second object 5 and the imaging lens 322 (not shown in FIG. 11) is important, which is needed to be precisely adjusted.

[0149] First, as shown in FIG. 11, the information terminal 305 is arranged in such a manner that the top of the antenna 32 is pointing toward the desk 51, and thereafter the information terminal 305 in an upside down posture with the antenna 32 in storage status is moved downward. When the top of the antenna 32 comes in contact with a surface of the desk 51, the information terminal 305 no longer keeps moving downward. In this manner, when the top of the antenna is in contact with the surface of the desk 51, the distance between the second lens portion 362 and the second object 5 is being optimized. Subsequently, with the top of the antenna 32 being kept in contact with the surface of the desk 51, the second object 5 is imaged using the second lens portion 362.

[0150] According to the seventh embodiment, the following effects can be obtained in addition to the similar effects to those of the aforementioned fourth embodiment. Since the length of the antenna 32 is defined with respect to imaging of the second object 5, the distance between the information terminal 305 and the second object 5 (e.g., a bar code) can be easily optimized in such a manner that the information terminal with the antenna 32 in storage status is moved downward until the top of the antenna 32 comes in contact with the surface on which the second object 5 is arranged (e.g., a surface of the desk 51).

[0151] Further, in this seventh embodiment, with a length of the antenna 32 defined as 15 mm, a focal length of the first lens portion 361 (not shown in FIG. 11) of the imaging lens 322 defined as 5 mm, and a focal length of the second lens portion 362 defined as 3.8 mm, an imaging of a two-dimensional bar code as the second object 5 at a distance of 15 mm is tried, and then an excellent image was obtained that improved a decoding precision of the two-dimensional bar code. In addition, when an imaging using the first lens portion 361 was performed, it was able to focus on a person at a distance of approximately 30 cm to 50 cm.

[0152] When a close-up imaging using the second lens portion 362 is performed, the information terminal 305 is positioned to be upside down. However, regarding an image display on the liquid crystal display device 13, an image of a close-up imaging in progress and an image of a decoding result can be easily readable by reversing vertical and horizontal scanning directions.

[0153] Furthermore, in this seventh embodiment, the adopted imaging lens 322 is a multifocal lens composed of the second lens portion 362 in a ring shape and the first lens portion in a circular shape formed in one piece, so that the information terminal 305 can be miniaturized in size and simplified in handling and operation.

[0154] In addition, an imaging lens identical to the imaging lens 22 composed of the first lens portion 61 and the second lens portion 62 of the information terminal 1 of the aforementioned first embodiment (refer to FIG. 1) may also be adopted as the imaging lens.

[0155] (Eighth Embodiment)

[0156]FIG. 12 is an explanatory view showing a usage of an information terminal 306 of an eighth embodiment of the present invention.

[0157] The information terminal 306 is a portable type information terminal including a wireless transmitting/receiving mechanism for example, which has an internal structure identical to that of the information terminal 302 (refer to FIG. 8) of the aforementioned fourth embodiment, so that the same reference numerals are designated to the same components to omit explanations in detail.

[0158] In FIG. 12, similarly to the information terminal 302 of the aforementioned fourth embodiment, the information terminal 306 includes the imaging lens composed of the first lens portion 361 having a front shape in circular shape (not shown in FIG. 12) and the second lens portion 362 having a front shape in ring shape formed in one piece, and the liquid crystal display device 13 as a display means. In addition, an illumination means not shown in the view is attached to the liquid crystal display device 13.

[0159] In the eighth embodiment, the information terminal 306 performs an imaging of a bar code 10 as a second object as follows. As shown in FIG. 12, the bar code 10 as the second object is printed on a recording paper 9, and this bar code 10 is read using the second lens portion 362. At this time, the reading of the bar code 10 is performed while it is illuminated by the illumination means attached to the liquid display device 13. Thereafter, when decoding of information included in the bar code 10 is completed, the completion of decoding is notified by a buzzer or a light, and if necessary, a decoding result is displayed on the liquid crystal display device 13.

[0160] Furthermore, since the bar code 10 includes information such as a telephone number, e-mail address, URL address, or the like, various processing are performed such as a telephone call or displaying a homepage based on a obtained decoding result such as a telephone number, address, or the like, for example, as disclosed in the Japanese Patent Application Laid-open

[0161] Therefore, according to the eighth embodiment, in addition to the similar effects to those of the aforementioned fourth embodiment, a clear image can be obtained to improve the decoding precision by performing the reading of the bar code 10 while it is illuminated by an illumination of the illumination means attached to the liquid display device 13.

[0162] (Ninth Embodiment)

[0163]FIG. 13 is an explanatory view showing a usage of an information terminal 307 of a ninth embodiment of the present invention. This ninth embodiment is an example of reading a bar code 105 as a second object when it is printed in invisible ink that emits a fluorescent light of a specific color upon irradiation of excitation light 100. The bar code 105 is printed in invisible ink that is cannot be recognized by the unaided eye, which emits a light with a longer wavelength than that of the excitation light 100 that is used for irradiation.

[0164] Since the information terminal 307 has a structure substantially identical to that of the information terminal 304 of the aforementioned sixth embodiment (refer to FIG. 10), the same reference numerals are designated to the same components to omit explanations in detail and only the different components will be explained below.

[0165] In this ninth embodiment, a light filter 101 is arranged between the bar code 105 and the imaging device 21. This light filter 101 let through a light with a wavelength of invisible ink emitted upon irradiation of the excitation light 100 to the bar code 105 using the illumination lamp 44 and blocks a light with other wavelength.

[0166] In addition, in this ninth embodiment, instead of the imaging lens 322 of the information terminal 304 of the aforementioned sixth embodiment (refer to FIG. 10), an imaging lens identical to the imaging lens 22 of the information terminal 1 of the aforementioned first embodiment (refer to FIG. 1) is used.

[0167] Therefore, according to the ninth embodiment, in addition to the similar effects to those of the aforementioned sixth embodiment, the contrast can be improved since the light filter 101 is included, so that the image from the invisible ink can be clearly imaged.

[0168] Generally, on the recording paper 9 on which the bar code 105 is recorded, it is quite common to have not only the bar code 105 printed in invisible ink but also things printed in printing ink that is visible to the unaided eye other than the bar code 105. Accordingly, it is necessary to selectively recognize only the light emitted from invisible ink for decoding information included in the bar code 105 printed in invisible ink. In this ninth embodiment, since the light filter 101 is adopted, the light emitted from invisible ink is selectively directed to the imaging device 22, and a light reflected from other printing ink is blocked, so that a clear image of the bar code 105 can be obtained. In addition, an excellent result can be obtained when an ultraviolet ray is used as the excitation light 100.

[0169] In a case that a lighting is provided only by the excitation light 100 with no other illumination light than the excitation light 100, only a part printed in invisible ink emits light, and therefore it is not necessary to use the light filter 101.

[0170] In addition, in this ninth embodiment, the light filter 101 is arranged between the imaging lens 22 and the imaging device 21, but the light filter 101 may also be arranged between the bar code 105 and the imaging lens 22.

[0171] Furthermore, in this ninth embodiment, the imaging lens identical to the imaging lens 22 of the information terminal 1 of the aforementioned first embodiment 1 (refer to FIG. 1) is adopted, but an imaging lens identical to the imaging lens 322 of the information terminal 304 of the aforementioned sixth embodiment (refer to FIG. 10) may also be adopted.

[0172] (Tenth Embodiment)

[0173]FIG. 14 is an overall structure view showing an information terminal 308 of a tenth embodiment of the present invention.

[0174] In FIG. 14, the information terminal 308 has a structure substantially identical to that of the information terminal 302 (refer to FIG. 8) of the aforementioned fourth embodiment except the differences in composition of the image memory 12 and processing method of an image data, so that the same reference numerals are designated to the same components to omit explanations in detail, and only the different components will be explained below.

[0175] The image memory 12 is respectively divided for three colors of an image signal into a red image memory 12R, a green image memory 12G, and a blue image memory 12B.

[0176] Further, there are composed a compensation means by the control program 16 and the CPU 15 for compensating a signal stored in the red image memory 12R according to a signal stored in the green image memory 12G or the blue image memory 12B.

[0177] In the tenth embodiment, the information terminal 308 performs an imaging of a bar code 105 (refer to FIG. 13) as a second object as follows. 25 At this time, as shown in the aforementioned ninth embodiment, on the recording paper 9 as the second object, it is quite common to have not only the bar code 105 printed in invisible ink but also objects printed in printing ink that is visible to the unaided eye other than the bar code 105. Accordingly, it is necessary to selectively recognize only the light emitted from invisible ink for decoding information included in the bar code 105 printed in invisible ink.

[0178] When the bar code 105 printed in invisible ink is exposed to an ultraviolet ray, it emits a light with a long wavelength that increases the red signal. However, as describe above, the signal stored in the red image memory 12R include not only the signal of the bar code 105 but also signals of other objects printed in normal ink on the recording paper 9. For that reason, the compensation means adjusts an amplitude of a signal in the green image memory 12G or the blue image memory 12B, both of which do not receive signals from invisible ink, and then subtracts the adjusted signal from the signal in the red image memory 12R to thereby produce a clear image of the bar code 105 emitted from the invisible ink.

[0179] According to the tenth embodiment, in addition to the similar effects to those of the aforementioned fourth embodiment, a clear image of the bar code 105 emitted from the invisible ink can be produced in order to precisely read the information included in the bar code 105 in such a manner that the compensation means adjusts an amplitude of a signal in the green image memory 12G or the blue image memory 12B and then subtracts the adjusted signal from the signal in the red image memory 12R.

[0180] (Eleventh Embodiment)

[0181]FIG. 15 is an explanatory view showing a usage of an information terminal 309 of an eleventh embodiment of the present invention.

[0182] The information terminal 309 has a structure substantially identical to that of the information terminal 304 of the aforementioned sixth embodiment (refer to FIG. 10) except the differences in composition of the image memory 12, processing method of an image data, and composition of image lens, so that the same reference numerals are designated to the same components to omit explanations in detail, and only the different components will be explained below.

[0183] The image memory 12 is divided into an irradiated image memory for storing an image signal A generated when invisible ink emits light upon irradiation of excitation light 100, a pre-irradiation image memory for storing an image signal B of the imaging device 21 before performing irradiation of the excitation light 100, and a compensated image memory for storing a signal A-B that is generated by subtracting the image signal B from the image signal A.

[0184] Further, there are composed a difference operation processing means by the control program 16 and the CPU 15 for generating an image of the bar code 105 as the second object based on a difference between an image signal obtained by imaging the bar code 105 as the second object with irradiation of the excitation light 100 thereon and an image signal obtained by imaging without irradiation of the excitation light 100.

[0185] Further, in this eleventh embodiment, instead of the imaging lens 322 (refer to FIG. 10) of the information terminal 304 of the aforementioned sixth embodiment, an imaging lens identical to the imaging lens 22 of the information terminal 1 of the aforementioned first embodiment (refer to FIG. 1) is adopted.

[0186] In the eleventh embodiment, the information terminal 309 performs an imaging of the bar code 105 as follows. As shown in FIG. 15, when imaging the bar code 105 on a recording paper 9, the image signal B in the imaging device 21 before performing the irradiation of the excitation light 100 is stored in the pre-irradiation image memory, and then the image signal A generated when invisible ink emits light upon irradiation of the excitation light 100 is stored in the irradiated image memory. Subsequently, the difference operation processing means generates an image signal of the bar code 105 from the difference A-B between the signal A and the signal B and then stores the operation result in the compensation image memory.

[0187] At this time, the image signal A which is generated when invisible ink emits light upon irradiation of the excitation light 100 includes not only the signal from the bar code 105 but also signals of other objects printed in normal ink on the recording paper 9. However, the image signal B of the imaging device 21 before performing the irradiation of the excitation light 100 includes only the signals of objects printed in normal ink on the recording paper 9, and not the signal from the invisible ink. Therefore, a subtraction of the image signal B from the image signal A provides a clear image of the bar code 105 generated by the light emission of the invisible ink.

[0188] According to the eleventh embodiment, the following effects can be obtained in addition to the similar effects to those of the aforementioned sixth embodiment. The difference operation processing means provides an image signal of the bar code 105 by subtracting the image signal B before performing the irradiation of the excitation light 100 from the image signal A generated by light emission of the invisible ink, so that a clear image of the bar code 105 generated by light emission of the invisible ink can be obtained, and therefore information included in the bar code 105 can be appropriately read.

[0189] In addition, in this eleventh embodiment, the imaging lens identical to the imaging lens 22 of the information terminal 1 of the aforementioned first embodiment (refer to FIG. 1) is used, but an imaging lens identical to the imaging lens 322 of the information terminal 304 of the aforementioned sixth embodiment (refer to FIG. 10) may also be used.

[0190] Industrial Availability

[0191] As has been described, the information terminal according to the present invention is advantageous for various information terminals having an image input function such as a personal digital assistant (PDA), a mobile telephone (including the Personal Handy-phone System (PHS)), a remote controller for consumer electronics such as a television of a videocassette recorder, a personal computer equipped with a camera, a monitoring camera and so forth. The present invention is especially suitable when imaging a first object at a regular distance and a second object nearer than the first object and performing various processing such as communication, display, and so forth based on the information obtained by imaging the second object. 

1. An information terminal having an imaging lens and an imaging device for capturing an image formed by the imaging lens, wherein said imaging lens is a multifocal lens composed of a first lens portion having a first focal length for imaging a first object at a normal distance and a second lens portion having a second focal length for imaging a second object nearer than the first object, and the first lens portion and the second lens portion are arranged on a same plane and formed in one piece.
 2. The information terminal according to claim 1, wherein the same plane is orthogonal to an optical axis of said imaging lens.
 3. The information terminal according to claim 1, wherein a front shape of the first lens portion is any one of a circular shape, an oval shape, and a polygonal shape, a front shape of the second lens portion is a ring shape, and the second lens portion is arranged outside the first lens portion in concentric with the first lens portion.
 4. The information terminal according to claim 1, wherein a front shape of the first lens portion is a ring shape, a front shape of the second lens portion is any one of a circular shape, an oval shape, and a polygonal shape, and the first lens portion is arranged outside the second lens portion in concentric with the second lens portion.
 5. The information terminal according to claim 1, wherein a front shape of the first lens portion is any one of one portion of a circular shape, one portion of an oval shape, and one portion of a polygonal shape, and a front shape of the second lens portion is any one of the other portion of the circular shape, the other portion of the oval shape, and the other portion of the polygonal shape, and a linear portion formed on an outline of the first lens portion is arranged in direct contact with a linear portion formed on an outline of the second lens portion.
 6. The information terminal according to claim 1, wherein said imaging lens is formed of glass or plastic.
 7. The information terminal according to claim 1, further comprising an image memory for storing an image captured by said imaging device, wherein a first image obtained by imaging the first object is formed in a first image-forming section in said imaging device and then stored in said image memory as a first image signal, and a second image obtained by imaging the second object is formed in a second image-forming section in a different region from the first image-forming section in said imaging device and then stored in said image memory as a second image signal.
 8. The information terminal according to claim 1, further comprising an image memory, wherein a first image obtained by imaging the first object is stored in said image memory as a moving image or a still image, and a second image obtained by imaging the second object is stored in said image memory as a moving image or a still image.
 9. The information terminal according to claim 1, further comprising a decoding means for decoding a digital code or a character that is the second object, and a communication means for performing communication based on information included in a digital code or a character decoded by said decoding means.
 10. The information terminal according to claim 9, further comprising a notification means for notifying a completion of a decoding process by said decoding means.
 11. The information terminal according to claim 10, wherein said notification means is a speaker for producing a voice or a confirmation sound after a completion of a decoding process by said decoding means.
 12. The information terminal according to claim 10, wherein said notification means is a light-emitting mechanism for emitting a light signal after a completion of a decoding process by said decoding means.
 13. The information terminal according to claim 9, further comprising a display means for displaying a completion of a decoding process by said decoding means.
 14. The information terminal according to claim 9, further comprising a display means for displaying at lease one of either decoding result of a decoding process by said decoding means or communication result of said communication means.
 15. The information terminal according to claim 1, further comprising an optical shutter between said imaging lens and said imaging device for switching the first lens portion and the second lens portion.
 16. The information terminal according to claim 1, further comprising a light-emitting means for emitting a flashlight synchronously with scan timing of said imaging device when imaging the second object.
 17. The information terminal according to claim 1, further comprising a detection means for detecting a saturation current from said imaging device, and a drive means for driving a drive circuit of said imaging device according to a signal from said detection means.
 18. The information terminal according to claim 1, further comprising a color filter arranged on at least one side of a front or back face of said imaging lens, said color filter being used when imaging the second object.
 19. The information terminal according to claim 1, further comprising an image memory plurally divided for each color, and a compensation means for compensating a signal stored in one of divided image memories for respective colors according to a signal stored in one of the other divided image memories for respective colors.
 20. The information terminal according to claim 1, further comprising a difference operation processing means for producing an image of the second object based on a difference between an image signal obtained by imaging with irradiation of excitation light on the second object and an image signal obtained by imaging without irradiation of excitation light.
 21. The information terminal according to claim 1, further comprising a display means for displaying information on a screen and an illumination means attached to said display means for illuminating the second object by light emission from the screen of said display means when imaging the second object.
 22. The information terminal according to claim 1, further comprising an antenna for wireless transmitting and receiving, said antenna in storage status having a length that optimizes a distance between the second object arranged on a surface to which the top of said antenna comes in contact with and the second lens portion. 